MAR-APR 2018

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INTECH MARCH/APRIL 2018 19 PROCESS AUTOMATION owner to define. The recommendation is to em- brace the alarm class as a tool in site alarm man- agement work processes to help ensure effective requirement management of special types of alarms. In setting requirements for alarm classes, it can be effective to review the components of the ANSI/ISA-18.2 life cycle (figure 1). Per ANSI/ISA-18.2-2016, specific alarm man- agement considerations should include: l alarm prioritization l alarm documentation l human-machine interface design l operating procedures associated with these alarms l operator training and training documentation l alarm maintenance l alarm testing l alarm monitoring and assessment l alarm management of change l alarm history retention l alarm auditing When alarm management software is actively used to manage the alarm system, an alarm class can be a very effective cross-reference tool. The classification can help manage and record compli- ance with requirements and help prevent inadver- tent deletion of, or changes to, important alarms. Common types of classes Alarms can come from a variety of sources. The most common classes of alarms are related to personnel protection, safety, product quality, en - vironmental issues, and company or site policies. Assigning classes of alarms by only the source may seem attractive; however, the alarm source can have a wide variety of alarm management requirements. All functional safety alarms, for example, can have different requirements for training, testing, auditing, or documentation. Class assignment depends on the requirements of the grouped alarms. Highly managed alarms ANSI/ISA-18.2 introduced the concept of the highly managed alarm (HMA). HMAs by defini - tion require more administration and documen- tation. If HMA classes are used, the alarm philoso- phy requires the organization to define the criteria for assigning alarms to HMA classes. The designa - tion of alarm classes as highly managed should be based on essentials, including alarms for: l process safety that is critical to protecting hu man life (e.g., safety alarms) l personnel safety or protection l environmental protection l current good manufacturing practice l commercial loss l product quality l process licensor requirements l company policy Although this may seem to add paperwork and complexity for limited or no gain, experi- ence has shown it is an effective best practice for managing the requirements. Example alarm class: H2S toxic gas The detection of hydrogen sulfide gas (H2S) will likely have defined action and danger levels for different physical areas. Managing these alarms as a class defines these settings, special han - dling based on mode of operation, the human- machine interface (HMI) presentation, operator response, frequency of testing, training for staff, metrics for monitoring and reporting, and audit requirements. A problematic H2S monitor that routinely alarms might have its alarm set point raised to not report the "nuisance" spike. Masking that spike might hide a safety concern related to a routine spike of detected H2S during a sampling FAST FORWARD l Alarm management concepts are likely well integrated at sites that started with the ASM Consortium work in the 1990s or later with the publication of ISA-18.2 in 2009. l A common phenomenon of alarm management is an initial gain in performance, followed by a gradual erosion of benefits caused by many variations in operations. l Life-cycle management is critical for effective long-term operation, and the concept of alarm class helps manage the work process. Figure 1. ANSI/ISA-18.2 alarm management life cycle

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